ArrangementDcelVertex
Definition
A vertex record in a DCEL data structure. A vertex is always associated
with a point. However, the vertex record only stores a pointer to the
associated point, and the actual Point object is stored elsewhere.
A vertex usually has several halfedges incident to it, such that it is
possible to access one of these halfedges directly and to traverse all
incident halfedges around the vertex. However, the DCEL may also contain
isolated vertices that have no incident halfedges. In this case, the vertex
stores an isolated vertexinformation record, indicating the face that
contains this vertex in its interior.
Types
ArrangementDcelVertex::Halfedge


the corresponding DCEL halfedge type.

ArrangementDcelVertex::Isolated_vertex


the corresponding DCEL isolated
vertexinformation type.


ArrangementDcelVertex::Point


the point type associated with the vertex.

Creation
ArrangementDcelVertex v;


default constructor.

void

v.assign ( Self other)

assigns v with the contents of the other vertex.

Access Functions
All functions below also have const counterparts, returning nonmutable
pointers or references:
bool

v.is_isolated ()

returns whether the vertex is isolated (has no incident halfedges).


Halfedge*

v.halfedge ()

returns an incident halfedge that has v as its target.
Precondition:  v is not an isolated vertex. 


Isolated_vertex*

v.isolated_vertex ()

returns the isolated vertexinformation record.
Precondition:  v is an isolated vertex. 


bool

v.has_null_point ()

returns whether the vertex is not associated with a valid point (i.e. it
lies at infinity).


Point&

v.point ()

returns the associated point.
Precondition:  v() is associated with a valid point. 


Boundary_type

v.boundary_in_x ()

return whether the vertex has an infinite $$xcoordinate.


Boundary_type

v.boundary_in_y ()

return whether the vertex has an infinite $$ycoordinate.

Modifiers
void

v.set_halfedge ( Halfedge* e)

sets the incident halfedge, marking v as a regular vertex.


void

v.set_isolated_vertex ( Isolated_vertex* iv)

 
sets the isolated vertexinformation record, marking v
as an isolated vertex.


void

v.set_point ( Point* p)

sets the associated point.


void

v.set_boundary ( Boundary_type inf_x, Boundary_type inf_y)

 
sets v as a vertex at infinity.
Precondition:  Either inf_x or inf_y is not NO_BOUNDARY. 

See Also
ArrangementDcel
ArrangementDcelHalfedge
ArrangementDcelIsolatedVertex